[tsimionescu]

Only if you're the final consumer of that module - if you publish it so others use your module, the replace directive will be ignored and they will get a failed build (or have to add their own replace directive for your sub-dependency).

[morelisp]

Yes, but this is roughly the same as any packaging system - the ones that don't use DNS as a default namespace require you to add explicit package repositories, which is no more or less onerous than the replace directive.